Morning Alex
I was in your situation just 3 months ago. I'm a similar age (59) and with a similar PSA (71). I was also told that due to the high PSA (without a urine infection) I've certainly got PCa and it may have spread to the bones. One was a certainty and one was a possibility, and he was right.
Like you I thought that all my plans and retirement dreams were shattered. Sh***ing myself would be an understatement. But I could only think of practicalities and so I planned my exit, frantically writing a will (had one but needed changing), adding wifes name to my bank account, checking life insurance policy, deciding when and what to tell the kids, drawing up funeral wishes, all done at such speed that anyone watching would think I'd be dead the following week. In hindsight, how ridiculous was that, but that's how I'm wired.
The time between now and your bone scan results will be one of hightened worry and anxiety and nothing anybody says to you will change that. This is the worst time, but it does get better. Whatever your dianosis Alex, you will be around for many years to come.
I'd expect your path going forward will be very similar to mine - MRI (see you've had that), Biopsy then straight onto hormone blockers (Zoladex in my case), Nuclear bone scan, CT scan and then if both those scans are clear expect a PSMA PET scan (due to high PSA).
My only advice, for what it's worth, would be to avoid google and use these forums. Wish I'd known that.
All the best.